JPH06105225B2 - Appearance inspection device - Google Patents
Appearance inspection deviceInfo
- Publication number
- JPH06105225B2 JPH06105225B2 JP61188984A JP18898486A JPH06105225B2 JP H06105225 B2 JPH06105225 B2 JP H06105225B2 JP 61188984 A JP61188984 A JP 61188984A JP 18898486 A JP18898486 A JP 18898486A JP H06105225 B2 JPH06105225 B2 JP H06105225B2
- Authority
- JP
- Japan
- Prior art keywords
- periodic
- inspected
- photoelectric conversion
- analog signal
- light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Length Measuring Devices By Optical Means (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
Description
【発明の詳細な説明】 〈産業上の利用分野〉 この発明は、被検査物における周期性のある欠陥を感度
よく検出し得る外観検査装置に関する。The present invention relates to a visual inspection apparatus capable of detecting a periodic defect in an inspection object with high sensitivity.
〈従来の技術〉 従来、外観検査装置においては、被検査物たとえば軸受
の円筒ころの表面にレーザー光を一定の速度で走査し、
上記円筒ころの表面からの反射光を光電変換装置で光電
変換し、この光電変換装置で光電変換された信号を判別
装置で比較レベルと比較して二値化を行い、円筒ころの
異常・正常の判定を行っていた。<Prior Art> Conventionally, in an appearance inspection apparatus, an object to be inspected, for example, the surface of a cylindrical roller of a bearing is scanned with laser light at a constant speed,
The reflected light from the surface of the cylindrical roller is photoelectrically converted by the photoelectric conversion device, and the signal photoelectrically converted by this photoelectric conversion device is compared with the comparison level by the discriminating device to perform binarization, and the abnormality / normality of the cylindrical roller is detected. Was being made.
〈発明が解決しようとする問題点〉 ところで、円筒ころの表面には、砥石のドレス後におい
て周期的欠陥が生じる場合がある。この周期的欠陥は砥
石に対するドレス針の送り速度、砥石の回転数に依存し
ており、同一砥石を使った同一加工物においては同一周
期で現れる。そして、第３図に示すように、光電変換さ
れた信号に円筒ころの表面の周期的欠陥に対応した一定
周波数の微少レベルの周期信号が存在する。<Problems to be Solved by the Invention> By the way, a periodic defect may occur on the surface of the cylindrical roller after the dressing of the grindstone. This periodic defect depends on the feed speed of the dressing needle to the grindstone and the rotation speed of the grindstone, and appears in the same cycle in the same workpiece using the same grindstone. Then, as shown in FIG. 3, the photoelectrically converted signal has a periodic signal of a certain level and a small level corresponding to the periodic defect on the surface of the cylindrical roller.
ところが、上記従来の外観検査装置では、周期性を伴っ
た微少欠陥が存在しても光学信号波形を単に基準レベル
と比較して二値化して欠陥の有無を判定していたため、
周期性のある欠陥があっても、検出が不可能であるとい
う問題があった。すなわち、第３図に示すような周期的
な欠陥がある状態と、第４図に示すような周期的な欠陥
がない状態とを識別することができなかった。However, in the above-mentioned conventional appearance inspection device, even if there are minute defects with periodicity, the optical signal waveform is simply compared with a reference level to be binarized to determine the presence or absence of defects.
There is a problem that even if there is a periodic defect, it cannot be detected. That is, it was not possible to distinguish between a state having periodic defects as shown in FIG. 3 and a state having no periodic defects as shown in FIG.
そこで、この発明の目的は、光学信号波形の二値化によ
り判定していた従来の方法では検出できなかった周期的
な微少欠陥を感度よく検出できる外観検査装置を提供す
ることにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a visual inspection apparatus capable of sensitively detecting periodic microscopic defects that could not be detected by the conventional method that was determined by binarizing an optical signal waveform.
〈問題点を解決するための手段〉 上記目的を達成するため、この発明の外観検査装置は、
曲率のある滑らかな仕上面を有し、回転される被検査物
の表面に、コヒーレント光を一定の速度で上記被検査物
の回転軸線の方向にスキャンする走査装置と、上記被検
査物の表面からの反射光を受光して光電変換装置に結像
する受光装置と、上記光電変換装置のアナログ信号出力
のうち上記コヒーレント光の走査速度と被検査物表面の
スキャン方向線上に分布する周期的欠陥から決定される
特定周波数成分のアナログ信号を通過させるバンドパス
フィルタと、上記フィルタの出力と基準値とを比較して
上記被検査物の周期的欠陥を検出する判別装置とを備え
たことを特徴とする。<Means for Solving Problems> In order to achieve the above object, the visual inspection apparatus of the present invention is
A scanning device that has a smooth finished surface with a curvature and that scans coherent light on the surface of the rotating inspection object at a constant speed in the direction of the rotation axis of the inspection object, and the surface of the inspection object. A light receiving device that receives reflected light from the photoelectric conversion device and forms an image on the photoelectric conversion device, and a periodic defect distributed on the scanning direction line of the coherent light of the analog signal output of the photoelectric conversion device and the surface of the inspection object. A bandpass filter that passes an analog signal of a specific frequency component determined from the above, and a discriminating device that compares the output of the filter with a reference value to detect a periodic defect of the inspected object. And
〈実施例〉 以下、この発明を図示の一実施例により詳細に説明す
る。<Example> Hereinafter, the present invention will be described in detail with reference to an example shown in the drawings.
第１図において、１はコヒーレント光の光源であるレー
ザー、２はミラー、３は走査装置である光スキャナ、５
は集光レンズである。また、６は図示しない駆動ローラ
上に載置されて回転させられる被検査物である円筒こ
ろ、14は増幅器、20は受光装置であり、この受光装置20
はフレネルレンズ７と光彩絞り８と集光レンズ９とスリ
ット11と光電変換装置としての光電子増倍管12とからな
る。また、22はオン・オフ信号を受けて増幅器14のアナ
ログ出力の通過を制御するアナログゲート、23は円筒こ
ろの表面の周期性を伴った傷に対応した特定周波数成分
のアナログ信号を通過させるバンドパスフィルタ、24は
バンドパスフィルタ23のアナログ出力を整流して低域周
波数成分を通過させる整流ローパスフィルタ、25は整流
ローパスフィルタ24の出力と予め設定した基準値とを比
較して円筒ころの周期性を伴った傷を検出する判別装置
である。In FIG. 1, 1 is a laser which is a light source of coherent light, 2 is a mirror, 3 is an optical scanner which is a scanning device, 5
Is a condenser lens. Further, 6 is a cylindrical roller which is an object to be inspected and is placed on a drive roller (not shown), 14 is an amplifier, and 20 is a light receiving device.
Is composed of a Fresnel lens 7, an iris diaphragm 8, a condenser lens 9, a slit 11, and a photomultiplier tube 12 as a photoelectric conversion device. Further, 22 is an analog gate that receives the ON / OFF signal and controls the passage of the analog output of the amplifier 14, and 23 is a band that passes the analog signal of a specific frequency component corresponding to the scratch with the periodicity of the surface of the cylindrical roller. A pass filter, 24 is a rectifying low-pass filter that rectifies the analog output of the band-pass filter 23 to pass low frequency components, and 25 is a cycle of cylindrical rollers by comparing the output of the rectifying low-pass filter 24 with a preset reference value. It is a discriminating device for detecting a scratch with sex.
上記構成において、回転される円筒ころ６の円筒面に、
光スキャナ３からレーザー光を、回転軸線の方向に沿っ
て端から端まで一定走査速度で走査する。円筒ころ６に
はたとえば砥石のドレス時に周期的欠陥は発生するもの
であり、その周期はドレス針の送り速度，ドラムの回転
数に依存して同一周期で現れる。この円筒ころ６の円筒
面からの反射光が受光装置30の光電子増倍管12で光電変
換され、光学信号波形が得られ、このアナログ光学信号
波形が増幅器14で増幅され、アナログゲート22を通して
バンドパスフィルタ23に入力される。レーザー光の走査
速度が一定であるので、上記光学信号波形には、円筒こ
ろ６の周期的な傷と走査速度に応じた一定周波数をもつ
周期性信号が現れる。この周期的な傷に対応する特定周
波数成分のアナログ信号のみがバンドパスフィルタ23を
通過し、さらに整流ローパスフィルタ24で整流される。
このようにして周期的な傷に対応した周波数成分のアナ
ログ信号のみが得られる。判別装置25でこの周波数成分
のアナログ信号と基準値とが比較されて周期的傷の有無
が判定される。このように、円筒ころ６のスキャン方向
線上に分布する周期的な傷に対応する特定周波数成分の
信号のみが検出されるので、周期的な微少傷でも感度よ
く検出できる。また、光スキャナ３によって、回転され
る円筒ころ６の円筒面に、レーザー光を回転軸線の方向
に沿って走査するので、円筒面全域を検査することがで
きる。In the above configuration, on the cylindrical surface of the cylindrical roller 6 to be rotated,
Laser light is scanned from the optical scanner 3 along the direction of the rotation axis at a constant scanning speed from end to end. Cylindrical rollers 6 have, for example, periodic defects when the grindstone is dressed, and the period appears in the same period depending on the feed speed of the dressing needle and the rotation speed of the drum. The reflected light from the cylindrical surface of the cylindrical roller 6 is photoelectrically converted by the photomultiplier tube 12 of the light receiving device 30, an optical signal waveform is obtained, the analog optical signal waveform is amplified by the amplifier 14, and the band is passed through the analog gate 22. It is input to the pass filter 23. Since the scanning speed of the laser light is constant, the optical signal waveform shows periodic scratches on the cylindrical roller 6 and a periodic signal having a constant frequency according to the scanning speed. Only an analog signal of a specific frequency component corresponding to this periodic flaw passes through the bandpass filter 23 and is further rectified by the rectification lowpass filter 24.
In this way, only the analog signal of the frequency component corresponding to the periodic flaw is obtained. The discriminator 25 compares the analog signal of this frequency component with the reference value to determine the presence or absence of periodic scratches. In this way, only the signal of the specific frequency component corresponding to the periodic scratches distributed on the scanning direction line of the cylindrical roller 6 is detected, so that even the periodic minute scratches can be detected with high sensitivity. Moreover, since the optical scanner 3 scans the cylindrical surface of the rotated cylindrical roller 6 with the laser light along the direction of the rotation axis, the entire cylindrical surface can be inspected.
第２図は上記実施例の変形例を示す。この変形例は、バ
ンドパスフィルタ23、整流ローパスフィルタ24、判別装
置25からなる周期傷検出回路f1，f2…を複数並設し、各
バンドパスフィルタの中心周波数を異なる周波数に調整
して、異なる周期をもって現れた幾つもの周期的欠陥を
検出できるようにしたものである。FIG. 2 shows a modification of the above embodiment. In this modification, a plurality of periodic flaw detection circuits f 1 , f 2 ... Consisting of a bandpass filter 23, a rectifying lowpass filter 24, and a discrimination device 25 are arranged in parallel, and the center frequencies of the bandpass filters are adjusted to different frequencies. , It is possible to detect a number of periodic defects that appear with different periods.
〈発明の効果〉 以上の説明より明らかな如く、この発明の外観検査装置
は、曲率のある滑らかな仕上面を有し、回転される被検
査物の表面に、コヒーレント光を一定の速度で上記被検
査物の回転軸線の方向にスキャンする走査装置と、上記
被検査物の表面からの反射光を受光して光電変換装置に
結像する受光装置と、上記光電変換装置のアナログ信号
出力のうち上記コヒーレント光の走査速度と被検査物表
面のスキャン方向線上に分布する周期的欠陥から決定さ
れる特定周波数成分のアナログ信号を通過させるバンド
パスフィルタと、上記フィルタの出力と基準値とを比較
して上記被検査物の周期的欠陥を検出する判別装置とを
備えているので、被検査物の表面の微少な周期的欠陥を
簡単な構造でもって感度よく検出することができる。ま
た、走査装置によって、回転される被検査物の表面に、
コヒーレント光を回転軸線の方向に沿って走査するの
で、被検査物の表面のうち上記回転軸線の周りの周面全
域を検査することができる。<Effects of the Invention> As is apparent from the above description, the appearance inspection apparatus of the present invention has a smooth finished surface with a curvature, and the coherent light is applied to the surface of the object to be inspected rotated at a constant speed. Of the scanning device that scans in the direction of the rotation axis of the inspection object, the light receiving device that receives the reflected light from the surface of the inspection object and forms an image on the photoelectric conversion device, and the analog signal output of the photoelectric conversion device A bandpass filter that passes an analog signal of a specific frequency component determined from periodic defects distributed on the scanning direction line of the coherent light and the scanning direction of the surface of the inspection object, and compares the output of the filter with a reference value. And a discriminating device for detecting the periodic defects of the inspection object, it is possible to detect the minute periodic defects on the surface of the inspection object with a simple structure and with high sensitivity. In addition, the surface of the inspection object rotated by the scanning device,
Since the coherent light is scanned along the direction of the rotation axis, it is possible to inspect the entire peripheral surface of the surface of the object to be inspected around the rotation axis.
第１図はこの発明の一実施例を示す光学系統図、第２図
は別の実施例のバンドパスフィルタ、判別装置を複数並
設した状態を示すブロック図、第３図は周期性を有する
信号を含む光学信号波形を示す図、第４図は周期性のな
い光学信号波形を示す図である。 ３…走査装置、20…受光装置、23…フィルタ、25…判別
装置。FIG. 1 is an optical system diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing a state in which a plurality of bandpass filters according to another embodiment, and discriminating devices are arranged in parallel, and FIG. 3 has periodicity. FIG. 4 is a diagram showing an optical signal waveform including a signal, and FIG. 4 is a diagram showing an optical signal waveform having no periodicity. 3 ... Scanning device, 20 ... Light receiving device, 23 ... Filter, 25 ... Discriminating device.
Claims (1)
れる被検査物の表面に、コヒーレント光を一定の速度で
上記被検査物の回転軸線の方向にスキャンする走査装置
と、上記被検査物の表面からの反射光を受光して光電変
換装置に結像する受光装置と、上記光電変換装置のアナ
ログ信号出力のうち上記コヒーレント光の走査速度と被
検査物表面のスキャン方向線上に分布する周期的欠陥か
ら決定される特定周波数成分のアナログ信号を通過させ
るバンドパスフィルタと、上記フィルタの出力と基準値
とを比較して上記被検査物の周期的欠陥を検出する判別
装置とを備えたことを特徴とする外観検査装置。1. A scanning device which has a smooth finished surface having a curvature and scans the surface of an object to be rotated with coherent light at a constant speed in the direction of the axis of rotation of the object to be inspected. A light receiving device that receives reflected light from the surface of the object to be inspected and forms an image on a photoelectric conversion device, and a scanning speed of the coherent light among analog signal outputs of the photoelectric conversion device and a scan direction line of the surface of the object to be inspected. A bandpass filter that passes an analog signal of a specific frequency component determined from distributed periodic defects, and a discriminating device that compares the output of the filter with a reference value to detect periodic defects of the inspection object. A visual inspection device characterized by being provided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61188984A JPH06105225B2 (en) | 1986-08-12 | 1986-08-12 | Appearance inspection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61188984A JPH06105225B2 (en) | 1986-08-12 | 1986-08-12 | Appearance inspection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6344152A JPS6344152A (en) | 1988-02-25 |
| JPH06105225B2 true JPH06105225B2 (en) | 1994-12-21 |
Family
ID=16233352
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61188984A Expired - Lifetime JPH06105225B2 (en) | 1986-08-12 | 1986-08-12 | Appearance inspection device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06105225B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH064606U (en) * | 1992-06-23 | 1994-01-21 | 古河電気工業株式会社 | Surface inspection device for inspected objects |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49129585A (en) * | 1973-04-13 | 1974-12-11 | ||
| JPS528888A (en) * | 1975-07-11 | 1977-01-24 | Hitachi Denshi Ltd | Running object surface fault classify detector system |
| JPS5578217A (en) * | 1978-12-11 | 1980-06-12 | Babcock Hitachi Kk | Prediction system for resonant oscillation |
| JPS57184958A (en) * | 1981-05-11 | 1982-11-13 | Nippon Steel Corp | Roll mark detecting device |
| JPS59107758A (en) * | 1982-12-10 | 1984-06-22 | Kobe Steel Ltd | Method and device for detecting slag inclusion in hot flaw detection on surface of continuous casting material |
| JPS6035609A (en) * | 1983-08-06 | 1985-02-23 | Ohtsu Tire & Rubber Co Ltd | Radial tire |
-
1986
- 1986-08-12 JP JP61188984A patent/JPH06105225B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6344152A (en) | 1988-02-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |